Generally, thermo-fluid energy is converted into mechanical energy through a heat engine like an internal combustion engine or external combustion engine as means for supplying power to a driving body, or electric energy is converted into mechanical energy through an electric motor, so that power is generated and provided directly to the driving body or is provided to a connected system through a connection member like a gear or belt.
Further, fuel as means for producing electric power is burnt, and accordingly, a turbine is driven through a thermal cycle to generate rotational power. Otherwise, the rotational power is generated using natural energy like a wind force or flowing water. Using the rotational power, a generation apparatus is driven to produce the electric power.
With the rotational power or generation power obtained through the above processes, apparatuses are driven and variously used for their purpose, but in the energy converting process, thermo-fluid loss and friction loss may be undesirably caused. Accordingly, when the amount of energy obtained with respect to the amount of energy supplied is indicated as an energy efficiency, many endeavors for enhancing the energy efficiency have been made through the reduction of the energy loss.
In an electric air cooler for a cold air blow, an electric air cooler for an air conditioner, an electric air accelerator for a vacuum cleaner, and an electric air supplier for a fuel cell vehicle, for examples, a thermal fluid loss and a frictional loss are generally generated, and accordingly, many tries for improving their efficiency should be needed.
On the other hand, a naturally aspirated vehicle is configured wherein since a naturally aspirated internal combustion engine that sucks air in an air sucking process and supplies the air to a combustion chamber is not charged with the amount of air corresponding to the amount of air discharged by means of the air sucking resistance generated in an air suction pipe, there is a limitation in increasing the output, and so as to improve the charging efficiency, accordingly, an inertially pressurized and supercharged air supply type RAM-air charging system using a vehicle speed is adopted. However, the inertially pressurized and supercharged air supply raises the density of air of head wind only while the vehicle is being driven at a high speed and thus increases the charging efficiency, and accordingly, the inertially pressurized and supercharged air supply is limitedly applied to some of vehicles.
A supercharger like a turbocharger for a supercharged vehicle is mounted on an exhaust manifold exit port surface to drive a turbine wheel and a compressor wheel connected to the turbine wheel by using exhaust gas energy increased according to the load of an internal combustion engine, to compress sucked air, to raise the density of air, and to supply the air to the air suction pipe of the internal combustion engine, thereby increasing the charging efficiency and the output of the internal combustion engine. However, the supercharged vehicle having the turbocharger has a sufficient boost pressure in a high speed driving region, but causes low exhaust gas energy in a low speed driving region so that it does not obtain a desired boost pressure. At this time, disadvantageously, the response time of the vehicle is delayed upon the change of load between the low speed driving region and the dynamic region, an oil supply device is needed to protect the vehicle from exhaust heat, and the load of internal combustion engine is raised due to the increment of back pressure in the high speed driving region. So as to solve the above-mentioned problems, a variable turbocharger, a two-stage turbocharger, a twin charge integral type electrical auxiliary turbocharger, and a complex sequential type supercharging system have been developed and applied to obtain a desired boost pressure and to increase the charging efficiency. However, their structure becomes complicated due to the increment of the number of parts related thereto, and their manufacturing cost becomes high due to the addition of a control system.
A supercharger like a centrifugal supercharger for a supercharged vehicle is configured wherein a set of gear is rotated using a frictional force of a pulley connected through a belt to the rotational power of an internal combustion engine, an impeller is driven with the number of rotations raised by using a gear ratio, and the sucked air to the internal combustion engine is compressed and supplied to an air suction pipe, thereby enhancing the charging efficiency and the output of the internal combustion engine. However, a compressor is driven in proportion to the number of rotations of a crank shaft, so that the response characteristics of the vehicle are excellent upon the change of load of the internal combustion engine, but contrarily, the number of rotations of the internal combustion engine driving the impeller is low on low speed driving, thereby delaying the formation of the boost pressure to cause the delay of acceleration. Further, the number of rotations of the crank shaft is increased to cause the load of the pulley driving the gears to be raised, thereby disadvantageously increasing the driving loss of the internal combustion engine, the noise generated from a connection member, the amount of fuel consumed, and operationg costs.
Further, a naturally aspirated vehicle is configured wherein since a naturally aspirated internal combustion engine that sucks air in an air sucking process and supplies the air to a combustion chamber is not charged with the amount of air corresponding to the amount of air discharged by means of the air sucking resistance generated in an air suction pipe, there is a limitation in increasing the output, and so as to improve the charging efficiency, accordingly, the diameter of the air suction pipe is increased to enlarge the flow rate path, the surface of the air suction pipe is smooth to reduce the frictional resistance, or a vortex generation device is provided to enhance an inertial force. However, even if the loss of inertial energy of air flowing in the air suction pipe is reduced, the inertial energy is not almost changed just with the variation of the air flow, thereby failing to achieve a high charging efficiency. Further, the vortex generation device acts as a resistance in a portion of the operating region thereof.
Furthermore, a supercharged vehicle having a turbocharger or supercharger is configured to have an air or water cooling device mounted between an exit port of the supercharger and an air suction pipe of an internal combustion engine to lower the temperature of the compressed air supplied from a combustion chamber and to enhance the density of air, thereby improving the supercharging efficiency. If the vehicle stops or is slowly driven, however, cooling performance becomes bad to cause knocking or lower the charging efficiency, and accordingly, cooling capacity should be increased over the whole driving region. However, there is a limitation in mounting the cooling device if the size of the cooling device is increased to improve the cooling performance, and further, there is a limitation in enhancing the cooling efficiency through an electric fan mounted on the cooling device and through the increment of the number of cooling fins, which undesirably raises the manufacturing cost.